High electron mobility transistor (HEMT) devices with gate recess structures are one of many HEMT device types and are widely used in the industry. In such device structures, the depth of the gate electrode recessed into the epitaxial layer is altered to reduce the density of the two-dimensional electron cloud. However, the difficulty in such manufacturing processes is how to accurately control the uniformity of the gate recess depth on the entire wafer. Whether the gate recess depth is uniform or not will affect the performance and the overall electrical properties.
Therefore, development of a HEMT device with uniformity of gate recess structures is desirable.